Importance of Solid-state Lighting in Indoor Commercial Horticulture|
Article - September 5, 2017 By LarsonElectronics.com
Importance of Solid-state Lighting in Indoor Commercial Horticulture
The success of commercial horticulture, or the practice of growing crops and optimizing plant growth for profit, is highly dependent on the latest lighting technologies available in the market today, such as solid-state luminaries (LEDs).
As more cities turn to greenhouses in order to reduce risks related to climate change and improve accessibility of seasonal crops, efficient lighting systems must be used to ease the challenges of sustainable cultivation.
Drivers of Indoor Vertical Farming
Several key trends unfolding worldwide are responsible for this shift in preferred growing methods. Over population is driving demand for fresh vegetables and fruits – at a level that cannot be met solely using traditional farming. Land, which is required to grow crops outdoors, is being prioritized for residential and commercial spaces to cater to the rising population. Additionally, cost of acquiring land for agriculture is increasing due to its demand.
This is evident in small countries worldwide, from Singapore to the Netherlands. In particular, Singapore, due to limited space, imports most of its meat, vegetables and fruits from Malaysia, its neighbor, and China. Japan is also facing a similar dilemma, as researchers are currently pioneering vertical cultivation configurations to maximize crop yield and space.
In the Netherlands, researchers from HAS University of Applied Sciences are using artificial lighting systems to support vertical farming operations. The team uses plant factories to grow crops in a dense configuration, within or close to the city. Furthermore, because vertical configurations are well organized, researchers expect robots to be able to manage operations autonomously in the future.
Faster without Sunlight
Many people assume that traditional farming in natural, outdoor locations is the best way to grow plants. This is not exactly true for all crops. There are numerous issues with outdoor cultivation, which is why farmers invest in costly irrigation systems, pesticides and monitoring devices. Most of these solutions are designed to offer more control over the environment and growing patterns of plants. For example, some farmers setup nets and wiring over their crops to discourage birds from eating them. In indoor horticulture, this is not needed and the types of pesticides used are not as diverse, since growers have full control of water, nutrients and soil.
When using LED lighting systems for greenhouses, growers would not be susceptible to shifts in weather and outdoor conditions. They can ensure a constant schedule of light, with great accuracy, right down to the second (using a timer and time schedule) and during periods of power outage (using a backup generator).
Contradictions of Using Blue Light in Horticulture
Solid-state lighting systems allow specialists to experiment with different light colors during cultivation. Going beyond conventional white or full-spectrum lighting, the introduction of LEDs has made color selection easier to accomplish. Here at Larson Electronics, we have extensively covered the applications of colored lighting in indoor cultivation. Red is by far the most used and recommended light color for optimizing plant growth. A mix of other colors, such as green, blue and far-red bands, is also required to prevent defects and promote natural growth.
Other light colors, such as orange, yellow and violet, are not commonly used and don’t have significant applications in indoor cultivation. The reason some artificial lights look pink or purple in greenhouses is due to a mixture of red and blue (with white or green). Green is known to be a non-essential light for growing, because it is not well absorbed by plants. However, new studies have uncovered that the light color does indeed play an important role in plant growth.
Out of all the colors at one’s disposal, the effects of blue light should be understood thoroughly. Very small amounts of blue light are needed for indoor cultivation. Exposing plants to too much blue light will stun its growth and cause defects. The recommended ratio of blue light is capped at 5:1 (red:blue). Some specialists require even less, at roughly 10 percent or five percent.
When crops are exposed to blue bands, a unique photoreceptor, called cryptochromes, inhibits the production of a hormone, called auxins, that is responsible for root and stem growth. Small amounts of blue light are required to regulate plant growth, allowing it to mature to its intended size (plants that are too big suffer from numerous issues, such as droopy canopies and leaves, weak foundations, as well as low quality – sometimes tasteless – yields).
Contradicting the above, blue light is a salient component to maximizing plant growth. At this light range, stomata, or microscopic pores found under the leaves of plants that regulate carbon dioxide absorption and the release of oxygen, responds to exposure by increasing its openings. As a result, metabolic rates increase and growth is accelerated.
Based on the characteristics of blue light and its effects on plants, it is possible to conclude that cultivators use this light range to purposely suppress vertical growth and the over expansion of leaves, resulting in compact, robust yields. This level of control is critical and highly sought after by growers, because it allows the plants to stay healthy without taking up unnecessary space in the greenhouse.
Urban Farming and Economic Trends
City farming is set to revolutionize the way supermarkets buy produce and the way consumers access seasonal vegetables. According to a report from The Food and Agriculture Organization of the United Nations, around 800 million people worldwide cultivate vegetables or fruits in cities, which accounts for a mind-blowing 15 to 20 percent of food in the world. Cities are increasing their reliance on urban farming operations, in order to protect local restaurants and supermarkets.
For instance, Gotham Greens, a New York-based indoor greenhouse that specializes in herbs and microgreens, experienced a surge in demand for its green products from locations devastated by Hurricane Sandy and crippling blizzards that swept through the Northern US regions. The company produces up to 270 metric tons of produce on an annual basis. Co-founder Viraj Puri boasts that during those periods, vegetables from the grow houses were the only ones on the supermarket shelf in locations affected by large storms.
The rise of LEDs is making indoor horticulture cheaper to practice and master. Solid-state luminaries can reduce energy consumption by roughly 30 percent and the units come with an average lifespan of 50,000+ hours. Additionally, growers only have to focus on red and blue wavelengths to maximize growth, greatly reducing investments when getting started. LEDs are also very compact, allowing horticulture enthusiasts to setup artificial lighting systems in their backyard, closet or dedicated growing room inside a home or office.